A5044667987- Pulsars and Gravitational Waves Research
- Geophysics and Gravity Measurements
- Astrophysics and Cosmic Phenomena
- Astrophysical Phenomena and Observations
- Gamma-ray bursts and supernovae
- High-pressure geophysics and materials
- Geophysics and Sensor Technology
- Radio Astronomy Observations and Technology
- Advanced Operator Algebra Research
- Geometric Analysis and Curvature Flows
- Advanced Topics in Algebra
- Seismic Waves and Analysis
- Soil Moisture and Remote Sensing
- Earthquake and Tsunami Effects
- Planetary Science and Exploration
- Coastal and Marine Dynamics
- Synthetic Aperture Radar (SAR) Applications and Techniques
- Seismology and Earthquake Studies
- Wave and Wind Energy Systems
- GNSS positioning and interference
- Geophysical and Geoelectrical Methods
- Cosmology and Gravitation Theories
- Nuclear Physics and Applications
National Space Science Center
2012-2025
Chinese Academy of Sciences
2009-2025
China Academy of Space Technology
2015-2021
National Astronomical Observatories
2009-2013
Because of the lack long-term pulsed emission in quiescence and strong timing noise, it is impossible to directly measure braking index n a magnetar. Based on estimated ages their potentially associated supernova remnants (SNRs), we estimate values mean indices eight magnetars with SNRs, find that they cluster range 1–42. Five have smaller 1 < 3, interpret them within combination magneto-dipole radiation wind-aided braking. The larger > 3 for other three are attributed decay external torque,...
The Crab pulsar is a quite young, famous that radiates multi-wavelength pulsed photons. latest detection of GeV and TeV emission with an unprecedented signal-to-noise ratio, supplied by the powerful telescopes Fermi, MAGIC, VERITAS, challenges current popular models, can be valuable discriminator to justify high-energy-emission models. Our work divided into two steps. First, taking reasonable parameters (the magnetic inclination angle α = 45° view ζ 63°), we use high-energy data calculate...
The Vela pulsar represents a distinct group of γ-ray pulsars. Fermi observations reveal that it has two sharp peaks (P1 and P2) in the light curve, with phase separation 0.42 third peak (P3) bridge. location intensity P3 are energy dependent. We use three-dimensional magnetospheric model for annular core gaps to simulate curves phase-averaged phase-resolved spectra. found acceleration electric field along line gap region decreases height. Emission at high-energy GeV band originates from...
Pulsed high-energy radiation from pulsars is not yet completely understood. In this paper, we use the 3D self-consistent annular gap model to study light curves for both young and millisecond (MSPs) observed by Fermi Gamma-ray Space Telescope. The can generate emission short-period pulsars. regions are so large that they have enough electric potential drop accelerate charged particles produce γ-ray photons. For pulsars, region neutron star surface about half of cylinder radius, peak...
Pulsars have been recognized to be normal neutron stars, but sometimes argued quark stars. Submillisecond pulsars, if detected, would play an essential and important role in distinguishing stars from We focus on the formation of such submillisecond pulsars this paper. A new approach a pulsar (quark star) by means accretion-induced collapse (AIC) white dwarf is investigated. Under AIC process, we found that: (i) almost all newborn could initial spin period ∼0.1 ms; (ii) nascent (even with low...
Pulsed γ-ray emission from millisecond pulsars (MSPs) has been detected by the sensitive Fermi space telescope, which sheds light on studies of region and its mechanism. In particular, specific patterns radio PSR J0101-6422 challenge popular pulsar models, e.g., outer gap two-pole caustic models. Using three-dimensional annular model, we have jointly simulated curves for three representative MSPs (PSR J0034-0534, J0101-6422, J0437-4715) with distinct phase lags, present best results these...
The emission geometries, e.g. the region height, beam shape, and radiusto-frequency mapping, are important predictions of pulsar radiation model.The multiband radio observations carry such valuable information.In this paper, we study two bright pulsars, (PSRs B0329+54 B1642-03) observe them in high frequency (2.5 GHz, 5 8 GHz).The newly acquired data together with historical archive provide an atlas multi-frequency profiles spanning from 100 MHz to 10 GHz.We evolution pulse regions these...
Integrated pulse profiles at 8.6~GHz obtained with the Shanghai Tian Ma Radio Telescope (TMRT) are presented for a sample of 26 pulsars. Mean flux densities and width parameters these pulsars estimated. For eleven first high-frequency observations further four, our have better signal-to-noise ratio than previous observations. one (PSR J0742-2822) differs from previously observed profiles. A comparison 19 those other frequencies shows that in nine cases separation between outmost leading...
Abstract We have observed a glitch in the Crab pulsar (PSR B0531+21) 0.5–10 keV X-ray band with X-Ray Pulsar Navigation -I ( XPNAV -1) satellite. This occurred around 2017 November 8. Observations at radio frequency by Jodrell Bank observatory and Lovell telescope confirmed it to be largest ever observed. report results of observation this glitch. The measured rotation increase is Δ ν 0 = (14.3 ± 2.0) × 10 −6 Hz, corresponding fractional / (0.48 0.09) . Two transient components change are...
ABSTRACT The pulse profile of PSR B1133+16 is usually regarded as a conal double structure. However, its multi-frequency profiles cannot simply be fitted with two Gaussian functions, and third component always needed to fit the bridge region (between peaks). This would introduce additional, redundant parameters. In this paper, through comparison five fitting functions (Gaussian, von Mises, hyperbolic secant, square Lorentz), it found that secant function can best reproduce profile, yielding...
Determining radiation location observationally plays a very important role in testing the pulsar models. One-photon pair production strong magnetic field, $\gamma-e^{+}e^{1}$, is one of physical processes mechanisms. Photons near surface with sufficient energy will be absorbed magnetosphere and absorption optical depth for these GeV $\gamma$-ray photons usually large. In this paper, we include aberrational, rotational general relativistic effects calculate $\gamma$-B photons. Then use...
The Five-hundred-meter Aperture Spherical radio Telescope (FAST) has the potential to discover many new pulsars and phenomena. In this paper we mainly concentrate on how FAST can impact study of pulsar emission mechanism magnetospheric dynamics. Several observational programs heading direction are reviewed. To make full use superior performance maximize scientific outcome, these be arranged in different phases according their demands for conditions. We suggest that performed following test...
PSR B1821−24 is a solitary millisecond pulsar that radiates multi-wavelength pulsed photons. It has complex radio, X-ray, and γ-ray pulse profiles with distinct peak phase separations challenge the traditional caustic emission models. Using single-pole annular gap model suitable magnetic inclination angle (α = 40°) viewing (ζ 75°), we managed to reproduce its of three wavebands. found middle radio originated from core region at high altitudes, other two peaks relatively low altitudes. Two...
We study the X-ray phases of Crab pulsar utilizing 11-year observations from Rossi Timing Explorer, 6-year radio Nanshan Telescope, and ephemeris Jodrell Bank Observatory. It is found that in different energy bands Telescope show similar behaviors, including long-time evolution short-time variations. Such strong correlations between imply timing noises are both generated spin cannot be well described by monthly observatory. When using as references to noise, it has a significantly smaller...
In this paper, we first prove that a compact K\"ahler manifold is projective if it satisfies certain quasi-positive curvature conditions, including $S_2^\perp,\, S_2^+,\,\mbox{Ric}_3^\perp, \,\mbox{Ric}_3^+$ or $2$-quasi-positive $\mbox{Ric}_k$. Subsequently, with restricted holonomy group both and rationally conected some non-negative condition, $2$-non-negative
Anomalous X-ray Pulsars and Soft Gamma-Ray Repeaters have been generally recognized as neutron stars with super strong magnetic fields, namely "magnetars". The "magnetars" manifest that the luminosity in band are larger than rotational energy loss rate, i.e. $L_{X}>\dot {E}_{\rm rot}$, then radiation is coming from of field. Here it argued magnetars may not really exist. Some radio observational results contradicted magnetar model. (1) PSR J1852+0040 much rate ($L_{X}/\dot rot}\simeq...
Pulsars have been found more than 40 years. Observations from radio to gamma-rays present abundant information. However, the radiation mechanism is still an open question. It that annular gap could be formed in magnetosphere of pulsars (neutron stars or quark stars), which combines advantages polar cap, slot and outer models. emphasized observations some pulsars, normal millisecond gamma-ray (MSGPs) show would play a very important role. Here we observational theoretical evidences about gap....